Tube rolling on Modwright Sony 5400ES

I would like to replaced the stock 6SN7W tubes with Sylvania JAN-CHS-6SN7W tall bottle. Any difference in the metal base(6SN7 A L 4 stamped on top of tube), and the black base(6SN7 W B 5 stamped on top of tube)?

xavier112-07-2012 7:35am

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mechans Details Discussions Posts This discussion Message User 3,048 posts 12-07-2012 at 04:57pm Copy Comment URL Report Comment Edit Delete What really matters is the maker of the tube and then if you know that then you can tell what the date code might be.
mechans Details Discussions Posts This discussion Message User 3,048 posts 12-07-2012 at 05:00pm Copy Comment URL Report Comment Edit Delete I should have added that your choice "Sylvania Jan" is a very good on indeed!
tomcy6 Details Discussions Posts This discussion Message User 2,597 posts 12-07-2012 at 11:46pm Copy Comment URL Report Comment Edit Delete Well, Tube World, the high-end boutique online tube dealer, says the Sylvania metal base is regarded by many as the best US made 6SN7. Many will disagree with that, of course. The metal base are more rare so more expensive. The metal base and many black base Sylvanias are considered excellent tubes. What is printed on the black base?

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